Energy Storage Materials Research Articles

Functional metal-organic frameworks derived electrode materials for electrochemical energy storage: a review.

Pristine metal-organic frameworks (MOFs) are built through self-assembly of electron rich organic linkers and electron deficient metal nodes via coordinate bond. Due to the unique properties of MOFs like highly tunable frameworks, huge specific surface areas, flexible chemical composition, flexible structures and a large volume of pores, they are being used to design the electrode materials for electrochemical energy storage devices. As per the literature, MOFs (including manganese, nickel, copper, and cobalt-based zeolitic imidazolate frameworks (ZIFs), University of Oslo (UiO) MOFs, Hong Kong University of Science and Technology (HKUST) MOFs and isoreticular MOFs (IRMOFs)) have attracted much attention in the field of supercapacitors (SCs)/batteries. According to their dimensionality such as 1D, 2D and 3D, pristine MOFs are mainly used as SC materials. Highly porous materials and their composites are capable for intercalation of metal ions (Na+/Li+). Moreover, the supramolecular features (π⋯π, C-H⋯π, hydrogen bond interactions) of redox stable MOFs provide better insight for electrochemical stability. So, this review provides an in-depth analysis of pure MOFs and MOF derived composites (MOF composites and MOF derived porous carbon) as electrode materials and also discusses their metal ion charge storage mechanism. Finally, we provide our perspectives on the current issues and future opportunities for supercapacitor materials.

Evaluating the energy and economic performance of hybrid photovoltaic thermal system integrated with multiwalled carbon nanotubes enhanced phase change material

Photovoltaic thermal (PVT) systems represent an advanced evolution of traditional photovoltaic (PV) modules designed to generate electrical and thermal energy simultaneously. However, achieving optimal and commercially viable performance from these systems remains challenging. To overcome this issue, in this research, multiwalled carbon nanotube (MWCNT) enhanced phase change materials (PCMs) integrated with PVT system to enhance electrical and thermal performance has been studied. An experimental investigation with three different configurations, PVT, PCM integrated PVT (PVTPCM), and MWCNT enhanced PCM integrated PVT (PVTNePCM) systems, was carried out under varying solar radiations and a water flow rate of 0.013–0.016 kg/s compared to conventional PV system. A two-step technique was employed to formulate the nanocomposites, and the energy performance of both PV and PVT systems assessed experimentally. The performance of PVTPCM and PVTNePCM systems was evaluated using the TRNSYS simulation technique. The formulated nanocomposite exhibited a 71.43% enhancement in thermal conductivity, a significant reduction in transmittance up to 92% and remained chemically and thermally stable. Integration of NePCM in the PVT system resulted in a notable decrease in panel temperature and a 25.03% increase in electrical efficiency compared to the conventional PV system. The highest performance ratio and overall efficiency for PVTNePCM were 0.55 and 81.62%, respectively, at a flow rate of 0.013 kg/s. The energy payback periods of PVTNePCM, PVTPCM, and PVT setup were 4.7, 4.8 and 5.6 years, respectively. Additionally, a significant improvement in thermal efficiency were observed for PVTPCM and PVTNePCM systems compared to water-based PVT systems, due to the energy stored in the thermal energy storage material.

Kinetic analysis of the self-discharge of the NiOOH OER active phase in KOH electrolyte: insights from in-situ Raman and UV–Vis reflectance spectroscopies

NiOOH has been established as the active phase of NiO-based electrocatalysts in the alkaline Oxygen Evolution Reaction (OER). Here, we investigate the self-discharge behavior of NiOOH electrodes under open circuit potential (OCP) conditions in 1 M KOH electrolyte by monitoring phase changes via in-situ Raman and UV–Vis reflectance spectroscopies and performing kinetic analyses on the OCP and spectroscopic data. Our findings reveal a linear phase change from NiOOH to Ni(OH)2 over time, indicative of a 0th-order reduction reaction. Contrarily, the OCP evolution associated with this phase reduction displayed a combination of linear and exponential decay patterns as a result of various kinetics, including Faradaic processes and diffusion-controlled mechanisms, influencing the self-discharge potential over 1.25 V (vs RHE). An additional linear region at lower potentials (<1.25 V (vs RHE)) suggests that charge redistribution due to the phase change from α-Ni(OH)2 to β-Ni(OH)2 dominates the self-discharge, a behavior confirmed by in-situ UV–Vis reflectance spectroscopy. These findings highlight the effectiveness of combining in-situ Raman and UV–Vis spectroscopy with electrochemical data for real-time monitoring of electrochemical processes, here potential-dependent electrocatalyst phase changes, leading to a more detailed and accurate understanding of the dynamic behavior, phase change kinetics, and self-discharge behaviors of solid electrocatalysts that can guide the design of more efficient and durable energy storage and conversion materials.

Local structure of Amorphous carbon investigated by X-ray total scattering and RMC modeling

Amorphous carbon is a promising candidate as an energy storage material. In this paper, we performed an X-ray total scattering measurement, RMC modeling, and persistent homology analysis for amorphous carbon samples fabricated at two different heat treatment temperatures. According to the analysis of the nearest-neighbor carbon atoms and their angular histogram, the sample treated at higher temperature shows higher connectivity between carbon atoms than that treated at lower temperature. Furthermore, topological data analysis (persistent homology, PH) reveals quantitative results that relate ring structure and the connectivity between carbon atoms.

Ternary g-C3N4/Co3O4/CeO2 nanostructured composites for electrochemical energy storage supercapacitors

Extensive use of fossil fuels causes heavy discharge of carbon dioxide, depleting energy resources and this requires environmentally friendly and effective energy storage materials. Hybrid supercapacitors (HSCs) are recently developed as effective energy storage materials enabling high capacitance retention rate and quick charging. Herein, synthesis of two-dimensional g-C3N4 nanosheets supported onto three-dimensional flower-like Co3O4/CeO2 (CoCe) ternary synergistic heterostructures are developed as effective electrodes for hybrid supercapacitor applications. Addition of g-C3N4 produces substantial surface active sites, enabling its synergistic effect with CoCe to enhance electrochemical performance having exceptional conductivity. The CoCe/g-C3N4 ternary composite electrode exhibits a higher specific capacitance of 1088.3 F g−1 at 1 A g-1 with 96 % of recycling stability over 5000 cycles, which is ∼5.5 and ∼5 folds higher specific capacitance than the pristine g-C3N4 and CoCe electrodes. EIS analysis revealed that CoCe/g-C3N4 electrode offered reduced charge transfer resistance compared to pristine electrodes. The fabricated two-electrode HSC device displays outstanding retention after 10,000 cycles with an ultra-high specific capacitance of 119.8 F g−1, excellent energy density 37.4 Wh kg−1 and power density of 749.9 W kg−1. This research showcases the perspectives of CoCe/g-C3N4 ternary electrodes in hybrid supercapacitors and other renewable energy storage devices.

The Impact of Biowaste Composition and Activated Carbon Structure on the Electrochemical Performance of Supercapacitors.

The increasing demand for sustainable and efficient energy storage materials has led to significant research into utilizing waste biomass for producing activated carbons. This study investigates the impact of the structural properties of activated carbons derived from various lignocellulosic biomasses-barley straw, wheat straw, and wheat bran-on the electrochemical performance of supercapacitors. The Fourier Transform Infrared (FTIR) spectroscopy analysis reveals the presence of key functional groups and their transformations during carbonization and activation processes. The Raman spectra provide detailed insights into the structural features and defects in the carbon materials. The electrochemical tests indicate that the activated carbon's specific capacitance and energy density are influenced by the biomass source. It is shown that the wheat-bran-based electrodes exhibit the highest performance. This research demonstrates the potential of waste-biomass-derived activated carbons as high-performance materials for energy storage applications, contributing to sustainable and efficient supercapacitor development.

A review on progress and prospects of diatomaceous earth as a bio-template material for electrochemical energy storage: synthesis, characterization, and applications

AbstractThis comprehensive review explores the remarkable progress and prospects of diatomaceous earth (DE) as a bio-template material for synthesizing electrode materials tailored explicitly for supercapacitor and battery applications. The unique structures within DE, including its mesoporous nature and high surface area, have positioned it as a pivotal material in energy storage. The mesoporous framework of DE, often defined by pores with diameters between 2 and 50 nm, provides a substantial surface area, a fundamental element for charge storage, and transfer in electrochemical energy conversion and storage. Its bio-templating capabilities have ushered in the creation of highly efficient electrode materials. Moreover, the role of DE in enhancing ion accessibility has made it an excellent choice for high-power applications. As we gaze toward the future, the prospects of DE as a bio-template material for supercapacitor and battery electrode material appear exceptionally promising. Customized material synthesis, scalability challenges, multidisciplinary collaborations, and sustainable initiatives are emerging as key areas of interest. The natural abundance and eco-friendly attributes of DE align with the growing emphasis on sustainability in energy solutions, and its contribution to electrode material synthesis for supercapacitors and batteries presents an exciting avenue to evolve energy storage technologies. Its intricate structures and bio-templating capabilities offer a compelling path for advancing sustainable, high-performance energy storage solutions, marking a significant step toward a greener and more efficient future. Graphical Abstract

Single-Nanometer Spinel with Precise Cation Distribution for Enhanced Oxygen Reduction.

Designing spinel nanocrystals (NCs) with tailored structural composition and cation distribution is crucial for superior catalytic performance but remarkably challenging due to their intricate nature. Here, an aggregation growth restricted hot-injection method is presented by meticulously investigating the fundamental nucleation and aggregation-driven growth kinetics governing spinel NC formation to address this challenge. Through controlled collision probability of nuclei during growth, this approach enables the synthesis of spinel NCs with unprecedented, single nanometer (1.2nm). Single-nanometer CoMn2O4 spinel via this method exhibits a highly tailored structure with a maximized population of highly active octahedral Mn atoms, thereby optimizing oxygen intermediate adsorption during oxygen reduction reaction (ORR). Consequently, it exhibits a remarkable half-wave potential of 0.88V in ORR and leads to a superior power density (170.9mW cm-2) in zinc-air battery, outperforming commercial Pt/C and most reported spinel oxides, revealing a clear structure-property relationship. This structure design strategy is readily adaptable for the precise synthesis and engineering of various spinel structures, opening new avenues for developing advanced electrocatalysts and energy storage materials.

Recent Advances of Plastic Waste‐Derived Carbon Materials for Energy Storage, Environmental Remediation and Organic Synthesis Applications

AbstractThe escalating severity of plastic waste's impact on the ecological environment and human health emphasize the crucial importance of developing resource‐conserving disposal technologies for sustainable development. Carbon‐based materials possess extensive functional applications across various fields, however, their high production costs and heavy reliance on fossil fuels pose challenges. Plastic wastes serve as ideal precursors for the green and sustainable production of carbon‐based functional materials due to high carbon content and low‐cost. This review provides a comprehensive summary of recent research progress on plastic waste‐derived carbon materials (PWCMs) including primary strategies for constructing PWCMs and their current functional applications in energy storage, environmental remediation and organic synthesis.

Amplifying energy storage and production efficiency: Utilizing BaS3: Ni2S3: Sb2S3 synthesized from dithiocarbamate precursors for enhanced and sustainable energy solutions

During this period of increasing energy use, the scientific community and energy stakeholders have been closely monitoring electrochemical energy storage. In an attempt to enhance the functionality of charge storage devices, diethyldithiocarbamate ligand is employed as a chelating agent during the production of the novel BaS3: Ni2S3: Sb2S3. The semiconductor BaS3: Ni2S3: Sb2S3, which was made in an environmentally friendly manner, showed good photoactivity due to its 2.97 eV energy band gap and light absorption. The resultant chalcogenide had an average crystallite size of 19.69 nm and displayed outstanding crystallinity with mixed crystallographic phases. Furthermore, infrared spectroscopy was used to investigate metallic sulfide connections, and the findings indicated that they varied between 500 and 875 cm−1. This chalcogenide featured varied sites for electrochemical reactions due to its morphology. The electrochemical performance of BaS3: Ni2S3: Sb2S3 was assessed using a conventional three-electrode setup. With a specific capacitance of up to 1019.4 F g−1 and a power density of 11931.26 W kg−1, BaS3: Ni2S3: Sb2S3 has proven to be an excellent electrode material for energy storage. This remarkable electrochemical performance was further reinforced by the comparable series resistance (Rs) of 0.57 Ω. During electrocatalysis, the electrode produced an OER overpotential with a Tafel slope of 348 mV and 119 mV dec−1. In contrast, the overpotential and Tafel slope in terms of the HER activity and were 211 mV and 100 mV/dec, respectively.

α-Bi2Mo3O12: A Dual-Functional Material for Electrocatalytic Water Splitting and Supercapacitor Applications.

This study explores the functionality of α-Bi2Mo3O12 (BMO) as an electrocatalyst for water splitting and its suitability for supercapacitor applications. BMO was synthesized by the solvothermal method and characterized in pre-calcination [BMO (BC)], post-calcination [BMO (AC)], and base-etched forms [BMO (BE)]. Structural analysis confirmed the formation of α-Bi2Mo3O12 with well-defined crystallographic planes. Electrochemical analysis revealed that BMO (AC) exhibited the lowest overpotential for hydrogen evolution reactions (HER) and BMO (BC) exhibited the lowest overpotential for oxygen evolution reactions (OER), indicating its superior electrocatalytic activity. The Tafel slope and electrochemical impedance spectroscopy results confirmed the superior kinetics and charge transfer properties of BMO material. Furthermore, BMO samples demonstrated excellent stability during prolonged chronoamperometry (CA) testing for 12 h. For supercapacitor performances, the BMO (BE) exhibits a superior specific capacitance value of 398 F/g at 2.0 A/g. Thus, the BMO material delivers prominent electrocatalytic activity as well as supercapacitor performance. Overall, this study demonstrates the potentiality of α-Bi2Mo3O12 in different forms as a dual-functional material for efficient energy storage and conversion.

Designing multifunctional Nb2O5 rods with ZnO modified g-C3N4 hybrid material for energy storage and hydrogen evolution

Designing multifunctional Nb2O5 rods with ZnO modified g-C3N4 hybrid material for energy storage and hydrogen evolution

Productivity forecasting of the solar still with phase change material using LSTM and GRU neural networks

Abstract Solar desalination is one of the renewable energy techniques by which freshwater can be obtained economically. Solar desalination experiments are time and resource-consuming methods; there is a need for a robust system to identify the serviceability of the solar still in a specific region. The objective of this study is to develop a forecasting model using artificial neural networks to predict freshwater productivity. The study specifically aims to compare the accuracy of Long Short-Term Memory (LSTM) and Gated Recurrent Unit (GRU) neural networks in forecasting the productivity of Conventional Solar Stills (CSS) and Solar Stills with Phase Change Material (SSPCM). The current investigation involved analysing the experimental outcomes of a solar still that employed phase change material (PCM) and pin fins. Palmitic acid was implemented as the energy storage material and was placed beneath the absorber plate. The neural network model was trained and validated using time-series solar still experimental data. Different statistical measures were utilised to evaluate the accuracy of Long Short Term Memory (LSTM) and Gated Recurrent Unit (GRU). The results indicate that the freshwater productivity forecasted by LSTM exhibited greater accuracy than GRU. Specifically, the coefficient of determination values for LSTM were 0.96 and 0.98 for the CSS and SSPCM, respectively, which were better than the corresponding values for GRU.

A Multielectron and High-Potential Spirobifluorene-Based Posolyte for Aqueous Redox Flow Batteries.

The rising energy demand driven by human activity has posed pressing challenges in embracing renewable energy, necessitating advances in energy storage technologies to maximize their utilization efficiency. Recent studies in aqueous organic redox flow batteries have focused primarily on the development of organic negative electrolytes, while the progress in organic positive electrolytes remains constrained by limitations in their redox potentials and effective electron concentrations. Herein, we report a spatially twisted chlorinated spirobifluorene ammonium salts (CSFAs), created through an unexpected green chlorination-protection pathway during the initial cycling in the flow battery cell, utilizing chloride ions from counterions in aqueous solution. The chlorinated, nonplanar spiral structure of CSFAs possesses a one-step four-electron transfer electrochemical property and offers exceptional resistance to nucleophilic attacks, exhibiting an unprecedented redox potential as high as 1.05 V (vs. SHE). A full redox flow battery based on CSFA-Cl (chloride ions as the counter ions) with 1.4 M electron concentration achieved an average coulombic efficiency exceeding 99.4 % and a capacity utilization reaching 95 % of the four-electron capacity for a stable cycling over 250 cycles (~22 days). The present work exemplifies the use of side reactions to develop new redox species, which can be extended to create more structurally versatile energy storage materials.

Ti3C2Tx-MXene based 2D/3D Ti3C2–TiO2–CuTiO3 heterostructure for enhanced pseudocapacitive performance

Ti3C2Tx MXene family is a promising electrode material for electrochemical energy storage, but it suffers from insufficient pseudocapacitive charge storage because of self-aggregation and oxidation degradation. To resolve the issue, this paper proposes a two-step process for synthesizing oxidation-controlled MXene-derived 2D/3D heterostructures that beneficially utilize oxidation and simultaneously improve conductivity. The first step generates in-situ 3D floral Ti3C2– TiO2 nanoribbons under partial oxidation of MXene. As the second step, further controlled oxidation with Cu ions transforms the 3D floral Ti3C2–TiO2 nanoribbons into 2D/3D Ti3C2–TiO2–CuTiO3 heterostructure. Leveraging the synergistic effects of MXene, TiO2, and CuTiO3, this 2D/3D heterostructure enhances the interlayered spacing, redox-active site concentration and alleviates low conductivity issue associated with TiO2 nanoribbons. At 2 mA/cm2, the proposed 2D/3D Ti3C2–TiO2–CuTiO3 heterostructure achieved a significantly higher capacitance of 599.2 mF/cm2, compared to MXene with a capacitance of 249.16 mF/cm2 and 3D floral Ti3C2–TiO2 nanoribbons with 498.5 mF/cm2. For practical evaluation, an asymmetric supercapacitor (ASC) device (Ti3C2–TiO2–CuTiO3//AC) was fabricated, which exhibited an energy density of 31.1 Wh/kg, power density of 1041.7 W/kg and capacitance retention of 83.7 % after 5000 continuous charging/discharging cycles. It opens new avenues for utilizing controlled oxidation to enhance pseudocapacitive properties.

Hydrophilic Ultra-Fine SiC Nanowires Enhance the Performance of Hydrated Salt Phase-Change Energy Storage Materials.

In this study, ultrafine linear nanostructured SiC with high wettability and large specific surface area were synthesized via the carbothermal reduction method. These nanowires were impregnated with Na2SO4 ⋅ 10H2O, CaCl2 ⋅ 6H2O, MgCl2 ⋅ 6H2O, and CaMg2Cl6 ⋅ 12H2O to obtain composite phase change materials (CPCMs), which demonstrated improved phase separation and significantly reduced supercooling. In particular, the supercooling degree of CaCl2 ⋅ 6H2O was minimized to 0.1 °C. The SiC nanowires effectively prevented issues of dehydration and deliquescence in hydrated salts. The thermal storage capacities of the CPCMs exceeded 90 %, with Na2SO4 ⋅ 10H2O and MgCl2 ⋅ 6H2O reaching 107.10 % and 103.35 %, respectively. Furthermore, the CPCMs exhibited greater sensitivity to changes in temperature compared with the pure hydrated salt phase change materials (PCMs). These results indicate that ultra-fine SiC nanowires can act as a versatile carrier for hydrated salt PCMs at low and intermediate temperatures.

Performance analysis of triple basin solar still with energy-exergy analysis approach

An experimental investigation was conducted on novel design of triple basin solar still with different modification in the climatic conditions of India. The triple basin solar still was modified with attachments of evacuated tubes (ETCs), heat pipes (HP), corrugated surfaces and energy storage materials called modified triple basin solar still (MTBSS). To get the more water in distillate output and higher water temperature solar still was designed with three basin area. From experimental results it was found that the total distillate output obtained by MTBSS during day and night was 16.46 l/m2 and 7.40 l/m2, respectively. The performance of MTBSS was also check by 4E (Energy, Exergy, Exergo-Economic, Exergo-Environmental) analysis for economical and environmental point of view. The generation of exergy for evaporation (Exe,bw-ig) and convection (Exc,bw-ig) for MTBSS (Modified triple basin solar still) were 24.03 &amp; 1.30 (joule) respectively. The values of energy efficiency (ƞenergy) and exergy efficiency (ƞexergy) obtained for MTBSS were 31.89% &amp; 3.04% respectively. An economic point of view, the CPL of water remains higher in MTBSS. The NPBT for MTBSS was 2.5 months. For environmental assessment, the CO2 mitigation for MTBSS was 0.48 t/year, based on the exergy approach. The additions of ETCs, H.P, corrugated surface, and ESMs with MTBSS are effective from an exergo-economic and carbon credit point of view.

Manganese Oxide-Doped Hierarchical Porous Carbon Derived from Tea Leaf Waste for High-Performance Supercapacitors.

Hierarchical porous carbon derived from discarded biomass for energy storage materials has attracted increasing research attention due to its cost-effectiveness, ease of fabrication, environmental protection, and sustainability. Brewed tea leaves are rich in heteroatoms that are beneficial to capacitive energy storage behavior. Therefore, we synthesized high electrochemical performance carbon-based composites from Tie guan yin tea leaf waste using a facile procedure comprising hydrothermal, chemical activation, and calcination processes. In particular, potassium permanganate (KMnO4) was incorporated into the potassium hydroxide (KOH) activation agent; therefore, during the activation process, KOH continued to erode the biomass precursor, producing abundant pores, and KMnO4 synchronously underwent a redox reaction to form MnO nanoparticles and anchor on the porous carbon through chemical bonding. MnO nanoparticles provided additional pseudocapacitive charge storage capabilities through redox reactions. The results show that the amount of MnO produced is proportional to the amount of KMnO4 incorporated. However, the specific surface area of the composite material decreases with the incorporated amount of KMnO4 due to the accumulation and aggregation of MnO nanoparticles, thereby even blocking some micropores. Optimization of MnO nanocrystal loading can promote the crystallinity and graphitization degree of carbonaceous materials. The specimen prepared with a weight ratio of KMnO4 to hydrochar of 0.02 exhibited a high capacitance of 337 F/g, an increase of 70%, owing to the synergistic effect between the Tie guan yin tea leaf-derived activated carbon and MnO nanoparticles. With this facile preparation method and the resulting high electrochemical performance, the development of manganese oxide/carbon composites derived from tea leaf biomass is expected to become a promising candidate as an energy storage material for supercapacitors.

Research Progress of Lignin-Derived Functional Materials for Electrochemical Energy Storage

Research Progress of Lignin-Derived Functional Materials for Electrochemical Energy Storage

The preparation and utilization of two-dimensional materials in electrochemical energy storage

The preparation and utilization of two-dimensional materials in electrochemical energy storage